Numerical benchmarking study of a selection of wave energy converters

Abstract

The aim of this study is to estimate the mean annual power absorption of a selection of eight Wave Energy Converters (WECs) with different working principles. Based on these estimates a set of power performance measures that can be related to costs are derived. These are the absorbed energy per characteristic mass [kWh/kg], per characteristic surface area [MWh/m 2 ], and per root mean square of Power Take Off (PTO) force [kWh/N]. The methodology relies on numerical modelling. For each device, a numerical Wave-to-Wire (W2W) model is built based on the equations of motion. Physical effects are modelled according to the state-of-the-art within hydrodynamic modelling practise. Then, the W2W models are used to calculate the power matrices of each device and the mean annual power absorption at five different representative wave sites along the European Coast, at which the mean level of wave power resource ranges between 15 and 88 kW per metre of wave front. Uncertainties are discussed and estimated for each device.Computed power matrices and results for the mean annual power absorption are assembled in a summary sheet per device. Comparisons of the selected devices show that, despite very different working principles and dimensions, power performance measures vary much less than the mean annual power absorption. With the chosen units, these measures are all shown to be of the order of 1.

Wave-actuated power take-off device for electricity generation

“…However, theoretical value is for monochromatic excitation without a practical limit on buoy excursion. Some confirmation that our CWR model results are reasonable is provided by the findings of numerical analyses reported by Babarit et al [23]. In particular the authors modeled a single tether version of our 3D-WEC and found a CWRs in the range of 0.021 to 0.042.…”

“…It is of interest to note that Babarit et al, [23] performed a numerical analysis of a bottom-tethered point absorber as shown in Figure 44 with a fully-submerge buoy which exhibits a better capture width ratio than the one of Figure 6A with a half submerged buoy. However, the authors do not report the degree of buoy buoyancy.…”

A Self-zeroing position controller for oscillating surge wave energy converters with strong asymmetry

“…As stated earlier panel methods assume inviscid flow and therefore ignore the viscous drag on the paddle. To compensate for this it is normal to apply a quadratic damping term Babarit et al (2012) like that in Eq. 6.…”

On the numerical modeling and optimization of a bottom-referenced heave-buoy array of wave energy converters

“…Assuming that the rigid arm connecting the float to the bearing is weightless, the hydrostatic stiffness coefficient K h expressed with respect to the axis of rotation can be computed as (Babarit et al, 2012):…”